The Difference Between Craniotomy and Craniectomy

Brain surgery is a very serious procedure, and if you or someone you love has been told brain surgery is necessary you must have many questions. Many brain surgeries start with opening the top of the skull to provide an opening through which the surgeon can work, although there are a few that are done through the nostrils with a small opening being made at the back of the nose. 

The Difference Between Craniotomy and Craniectomy
Verywell / Gary Ferster

The Craniotomy Procedure

A craniotomy is a surgery during which a piece of the skull—called a bone flap—is removed in order to allow a surgeon access to the brain. The bone flap is typically round or oval. The exact size and placement are determined by the nature of the procedure and what is to be accomplished during the surgery.

After the surgery is performed, the bone flap is usually returned to its previous location, where it can heal and mend like any broken bone. After several months the bone is nearly as strong as it was prior to surgery. In many cases, small metal plates are used to hold the bone flap in place so that it can heal, much like a cast for a broken arm.

The Craniectomy Procedure

A craniectomy procedure also includes the removal of a bone flap, but in this case, it is not returned to its location after the procedure is finished. This may be due to trauma to the bone itself, because the brain is too swollen to permit the return of the bone flap, or because the surgeon feels it is in the patient’s best interest. If there is an infection in the area, for example, the bone flap may be discarded.

Purpose of Craniotomy and Craniectomy

In some cases of brain trauma or injury, the entire purpose of the procedure is to perform a craniotomy or craniectomy—usually in order to reduce pressure by giving the brain room to swell. More commonly, many neurosurgeries start with either the craniotomy or craniectomy and once that is accomplished the neurosurgeon has access to the brain for the additional steps that are needed. 

For many procedures, think of the craniotomy/craniectomy as the incision being made in order for the procedure to be performed. Unlike an incision made in the abdomen or other areas of the body, the surgeon must go through the bone in order to complete the procedure. Like other incisions, this one will still require sutures or staples to close, as the skin on the head will need to be sewn like other more common types of incisions.

  • The bone flap is surgically removed and later returned to the skull after surgery

  • Often performed so the brain can be accessed for further surgery

  • The bone flap is surgically removed but is not returned to the skull after surgery

  • Often performed to relieve pressure on the brain

The Bone Flap

If a bone flap is removed, but not able to be returned during the procedure, it can still be put back into place at a later time. In this situation, the surgeon will place the bone flap in another location. In most cases, the surgeon will make an incision in the abdomen, large enough to slip the piece of bone inside like an envelope under the fatty tissue of the belly. There it is protected and preserved by the patient’s own body. Bone flaps can also be placed in a special deep freezer in the hospital lab for storage until it can be replaced.

If the bone flap cannot be returned, prosthetics and artificial bone are also available to aid the reconstruction at a later date. Replacing the missing piece is important because the brain is minimally protected without the bone in place. Like the "soft spot" on a newborn's head, the lack of bone could make it possible for a penetrating brain injury to occur. 

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  1. Johns Hopkins Medicine. Craniotomy.